Not all pain in the neck or back actually originates from the spine. Sometimes pain in the neck or back is caused by a problem in the shoulder or hip or from peripheral nerve compression in the arms or legs.
This article focuses on the diagnostic features of common—and uncommon—nonspinal musculoskeletal problems that can masquerade as disorders of the spine. A myriad of nonmusculoskeletal disorders can also cause neck or back pain, but they are beyond the scope of this article. Medical disorders that can present as possible spinal problems have been reviewed in the December 2007 issue of the Cleveland Clinic Journal of Medicine.
CAUSE OF NECK OR BACK PAIN IS NOT ALWAYS OBVIOUS
Pain in the neck or back is one of the most common reasons for visits to primary care physicians.
Usually the diagnosis is straightforward, but atypical pain patterns frequently make the cause of the problem difficult to decipher.1 Axial neck or back pain is in many cases caused by problems in the joints, muscles, tendons, or ligaments of the arms or legs because the nerves in these structures arise from the spinal cord.2 Because these structures can move relative to one another, pain often varies with position, further confusing the picture.2 Despite these challenges, a correct diagnosis can usually be made on the basis of the history, physical examination, and ancillary testing.
NONSPINAL MUSCULOSKELETAL CAUSES OF NECK PAIN
Many shoulder problems present as neck pain
Shoulder problems frequently cause neck pain4 because the shoulder and neck are near the brachial plexus, which connects them. The shoulder joint is a complex of several structures; problems in any of them can present with specific features that can be distinguished from neck problems.5
In general, shoulder problems in older people are due to degenerative conditions, whereas younger people generally have problems arising from trauma, inflammation, or instability.1
Rotator cuff disease is one of the most common shoulder problems that can present with neck pain. The rotator cuff consists of four muscles—the supraspinatus, infraspinatus, subscapularis, and teres minor—which form a common tendon that attaches to the proximal humeral tuberosities and allows rotation of the arm at the glenohumeral joint.1 The rotator cuff probably undergoes both mechanical and biologic degeneration over time, making it prone to painful tears.
Rotator cuff tears can cause pain in the anterolateral or medial aspect of the shoulder or in the trapezius and neck area.1,6 Many older patients present with pain in the trapezius and paraspinal muscles.2,5,7 Many patients report pain when they raise the arms over their head or when they reach and hold the arm away from the body (eg, holding the steering wheel while driving), and at night while lying on the affected side.1
On physical examination, weakness of the rotator cuff muscles can be detected by externally rotating the shoulder or applying a downward force to the arm with the shoulder abducted 90 degrees, forward flexed 30 degrees, and internally rotated with the thumbs pointing to the ground.1
Magnetic resonance imaging (MRI) can very accurately diagnose a rotator cuff tear: diagnostic findings include a discontinuity and retraction in the rotator cuff tendon and edema.
Not all rotator cuff tears are symptomatic.6 If a rotator cuff tear is evident on MRI but the patient does not have pain at night or during overhead activity, then neck pain is more likely due to spinal disease.
Glenohumeral arthritis is another common shoulder problem that can cause axial neck pain.1 Most cases are idiopathic, although many patients have a history of rheumatoid arthritis, prior shoulder trauma, or glenohumeral instability for which they may have had surgery. Patients with shoulder arthritis usually also have arthritis in the cervical spine.
Patients report pain in the trapezius muscle and possibly a sensation of swelling around the shoulder joint, as well as difficulty with overhead activities such as combing hair or applying makeup.1
The most significant clinical finding is eliciting the shoulder pain with motion. Patients may also have limited range of motion accompanied by pain and crepitation.1
Humeral head osteonecrosis is a less common intra-articular problem that can cause neck pain. It occurs most frequently with human immunodeficiency virus infection, alcoholism, or corticosteroid use.8 Radiography shows sclerosis or collapse of the subchondral bone of the humeral head. MRI is best for detecting early changes of osteonecrosis.